Suitability of Geotrichum candidum lipase for the stereospecific analysis of some triglycerides

A procedure is described for determining the stereospecific structure of triacid triglycerides containing oleic acid. The method utilizes the unique specificity of the lipase system from Geotricum candidum for hydrolyzing fatty acids which contain cis ‐9‐unsaturation. The procedure involves a pancreatic lipase hydrolysis of 10–20 mg of substrate to determine the fatty acids in the β‐position and the incubation of another 50 mg of triglyceride with G. candidum lipase to obtain diglyceride for further treatment. The α,α‐ and α,β‐diglycerides are collected separately, converted to phenyl phosphatides and treated with phospholipase A. The analysis of the monoglycerides, produced with pancreatic lipase and the analysis of the β‐lysophosphatides allows the determination of the ratios of the original 2 position oleic acid sn ‐triglycerides while the analysis of the α‐lysophosphatides aids in the determination of the original sn ‐triglycerides which contained oleic acid in the 3 position. The 1 position oleic acid sn ‐triglycerides are calculated by difference. Racemic and enantiomeric triglycerides containing palmitic, stearic and oleic acids were synthesized and used to establish the limits of the new method. The good agreement between the actual and observed values for a mixture of isomers indicates that the procedure will be useful in the analysis of triacid triglycerides which contain oleic acid. The application of the procedure to triacid triglycerides which contain other unsaturated fatty acids is discussed.